If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

battery shut off on ford power stroke

12-24-2012, 02:32 PM

I have a 2002 f250 power stroke with a bobcat 225 and i was wondering if you guys had battery shut offs on your rigs. I thought i read on 1 post that someone never used 1 and had no troubles toasting the computer while welding on the back of the truck. I put 1 on my frieghtliner and always used it before welding off the back of truck. I was wandering if there is something i dont know or is that guy just lucky he hasnt toasted his computer. So far i have always unhooked my batterys before welding off my f250's vise and unhooked the batterys on any truck with a computer that i was welding on. I have a heavy duty flaming river brand shut off to put on if needed. Any info would be helpful.

Used to have 99 powerjoke...had rhinolined bed. Tb302 on trailer, never unhooked when i welded and have never had an issue. That makes interesting thought tho as your alternator can be upwards of $175 or more. Id play safe if i were you unless you like fighting the tensioner pulley and replacing alternators. That was good engine ford put in from 99-03

Comment

I have a tb302 in the back of my 2009 f350 with the 6.4 litre powerstroke and have never had an issue and I weld on the tail gate when I need to, and I have no shut offs nor do I disconnect the batterys

Comment

Modern automotive electronics are MUCH more robust than those from the 80s, but they're still susceptible to overloads. And if the ground wire fails (due to mechanical damage or corrosion), a spike can fry a LOT more than just the PCM or alternator. So why push your luck? If you're welding on the truck such that the work lead (ground clamp) is grounded to the truck, unhook the truck's battery (or batteries). Since that may result in a lot of reprogramming (radio presets, clock, etc.), it's best to simply NOT weld on a grounded part of the truck. Rhino is a layer of polyurethane rubber, so it's a fantastic insulator. Even paint is an insulator, but it's easily scratched, so don't trust it. Throw a piece of cardboard or plywood down, and you can leave the battery hooked up.

Comment

Put my shut off switch in today. Couldn't bring myself to drilling holes anywhere in my bumper so i mounted it beside my passenger side battery. I have to pop the hood to turn it but thats easier then popping the hood to replace fried electrical parts. ( and cheaper ). Switch has a lock hole for out of service/theft protection which may come in handy 1 day.

Comment

The only reason i asked is cause have seen fellow employees fry alternators welding on trucks. Have only heard about computers getting fried. I had the shut off ( didn't cost me anything ) so better safe then sorry. And it gave me something to do.

Comment

I have never seen a welder fry an alternator. Seems to me I have seen ground wire get hot,,,, best I can recall when someone ground to body, work on frame etc but its been so long I cant remember details.
As Bob said,, at least a thoousand and this is a real number and maybe even light at that, even only once a week over 30 yrs would be over that, on occasions did one every day, sometimes worked off of truck bed several times a day.

I am sure it has happened somewhere at some time, at least something but never seen it personally, don't know any reliable first hand events either as I can recall and actually see more possibility of problems disconnecting etc and certainly giving more of a feeling of security than any real benifit.

I have heard stories,,, one remarkable one comes to mind on a forum, maybe here guy says he blew up his battery, cooked the alt and blew out all the light bulbs on his pickup truck and was here to let eveyone know,,, be sure to unhook battery, I said,,, send pics,,, I wanna see this, ha

These trucks are used as work platforms by welders by the thousands every day. If it was a problem we would hear about it.

Comment

How does disconnecting the batteries isolate the rest of the electrical system? Especially on newer vehicles there must be a dozen ground wires all over the truck so everything is interconnected. Disconnecting the batteries only isolates the batteries. The only time I had a problem was when the customer insisted on unhooking only the negative from the battery & the battery was dead when I finished. I never unhook unless the customer requests it & then I unhook both terminals.

You can always buy one of these. Not sure if they work. Always make sure you are grounded well & as close as possible to the weld.

Comment

[QUOTE=Sberry;298494]I have worked off a dozen trucks, welded on another 1000 at least, never unhooked. Never found anyone that could actually explain how it helped prevent anything.[/QUOTE.

I have seen computers fried from welding. Every time it was bad ground straps or lack of them. Current will find a ground path. If the grounds of the equipment or truck are good very unlikely of damage occuring. Also for everyone who fries alternators check the grounds. A bad ground is like pouring a bucket of water through a straw.
Kevin

Comment

and to offer some additional beat the horse to death perspective why, here is my 2 cents worth from the following point of view:

1) have done major welding work on a vehicle filled with computers, air bags, to make modifications for off roading

2) BUT I did buy the additional factory service and collision damage body repair manuals from the manufacturer as to how to do it without causing damage..

3) retired electrical engineer whose main career was knee deep in development work for a major computer company...

4) researched and published a few articles about the OBDII systems used on todays vehicles today..

still won't get you a cup of coffee, but here goes....

The thing to think about are the differences in the electrical path the welding current may take, depending on whether we are talking about welding ON a vehicle versus using a welder mounted on a truck for off truck welding...

When welding ON a vehicle the welding current is obviously being pulled through the vehicle between the point being welded on and where the welding ground clamp is attached.... Not so obvious is what happens for example if the ground clamp placed on the frame and welding on the body or vice/versa (e.g. as part of a body repair).. In this case welding current is being pulled across the electrical connection points between the body and the frame. Definitely need to stay away from this...

For a lot of people the complete path of the battery ground terminal...to body... to engine....to frame electrical connection.. is out of sight, out of mind.. Bad assumption when applying welding currents on a vehicle.

Reason: Think about it...for vibration and noise damping purposes, on most vehicles the frame to body mechanical connections end up being electrically isolated since rubber donuts are typically used at all points where the body is bolted to the frame... This could also include a pickup truck bed to frame.. The engine motor mounts and suspension/drivetrain similarly use rubber mounts that not only provide noise/vibration isolation, but also electrically isolate the drive train from frame.... The electrical bonding of body, engine/drivetrain and frame is done by ground straps, which in many vehicles tend to be light gauge, certainly not intended to carry welding current.

The computer systems do have to make connections across these boundaries; and connect to some sensors that may be isolated (protected from stray currents) and other sensors that use body ground as the return path, and put sensor (and computer) at more risk from stray currents.

The major point where body, drivetrain and frame are bonded together is the battery negative cable goes from the battery negative terminal to body ground, to frame ground, and then to the engine block, not necessarily in this order, or even done by the same cable.

If you take a look at this cable on your vehicle, most importantly the gauge of the wire from a typical welding current viewpoint, say for example a sustained duration current of 180 amps or so.. you may find it to be a mighty small gauge cable for that level of current..

Starter currents travel through this same wire can be much higher, but it's typically only seconds in duration which doesn't overheat the wire.

On a welder mounted on a truck where normal operation has both the ground clamp and stinger cables going to some distant point to the work, the body and frame of the truck does not become part of the welding current path and thus should have no problems.

If one does a lot of welding of material laying on the bed surface (or for example in a vice on the bed at the back of the truck, an additional permanent ground connection from the welder output terminal ground connection to the work surface would be good insurance against stray currents.

And most importantly, if your vice is mounted to the truck frame/bumper, it would be good insurance to extend the additional ground cable from the welder output ground terminal to the truck frame in the vicinity of where the vice is mounted.

Otherwise if you forget to put the ground clamp on metal that the vice is attached to and instead put the ground clamp on the bed, you could end up pulling welding current through the vehicle internal ground straps between the body(bed) and the frame which are too weak to handle that level of current. By adding your own heavy gauge strapping, this possibility is eliminated.